1. Field
Embodiments of the present invention relate generally to the cooling of work rolls in a rolling mill, and are concerned in particular with improving the cooling efficiency of liquid coolants such as water or the like applied to the roll surfaces.
2. Description of Related Art
In a known arrangement, as disclosed for example in U.S. Pat. No. 6,385,989 (Cassidy), a coolant delivery device partially surrounds a work roll and serves as a supply manifold for nozzles arranged to apply cooling water to the roll surface. Although such devices operate in a generally satisfactory manner, it has now been determined that their efficiency is compromised by the Leidenfrost effect, a phenomenon in which a liquid, in near contact with a body significantly hotter than the liquid's boiling point, produces an insulating vapor layer that keeps the liquid from boiling rapidly. The thermal conductivity of the vapor is much poorer than that of the liquid, resulting in reduced cooling efficiency.